Platelet Activating Factor
Platelet activating factor is a protein present in a variety of cells
throughout the body that participates in the activation of platelet,
leukocyte, and PLA2, which results in inflammatory and thrombotic
mechanisms. Many cell types produce platelet-activating factor
(1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine [PAF]), a
powerful lipid autocoid. When injected in vivo, PAF has a strong effect
on brain arteries and metabolism. PAF has direct neuronal actions in
vitro, such as suppression of acetylcholine release. Excessive PAF
production has been demonstrated in pathogenic nervous system conditions
such as neurotrauma and stroke (Yue & Feuerstein, 1994) . PAF synthesis
and release may be enhanced in SAH as a result of activated immune cells
and endothelial cells driven by thrombin and IL-1 (Khey, Huard &
Mahmoud, 2020). PAF produces tissue edema by increasing vascular
permeability in peripheral tissues, boosting platelet production of
granule-based enzymes, and increasing superoxide and arachidonate
metabolism in neutrophils, culminating in neurotoxicity and brain damage
following an ischemic stroke (Bladowski, Gawrys, Gajecki,
Szahidewicz-Krupska, Sawicz-Bladowska & Doroszko, 2020; Lindsberg,
Hallenbeck & Feuerstein, 1991; Zimmerman, McIntyre, Mehra & Prescott,
1990).